Traditionally, audience measurement entities determine audience size and demographic composition for media based on registered panel members. That is, an audience measurement entity enrolls people that consent to being monitored into a panel. The audience measurement entity then monitors the media habits of those panel members to identify media presentations (e.g., television programs, radio programs, Internet browsing, video on demand access, etc.) exposed to those panel members. The audience measurement entity can then determine the size and demographic composition of audience(s) for those media presentations based on the collected media measurement data.